Magnesium perchlorate



' as much as the latter.

Patented Dec- 10, 1929 GEORGE FREDERICK SMITH, OI UBBAQNA;

ILLINOIS MAGNESIUM PEBOHLOBA'IE 11o Drawing. Application filed June 13,

This invention relates to magnesium perchlorate and is herein disclosed as applied to a special anhydrous form together wlth a process for producing it.

According to the present invention the magnesium perchlorate may be cheaply prepared in granular form by grinding together suitable amounts of ammonium perchlorate and magnesium oxide or magnesium carbonto ate, followed by heating.

Suitable quantities, as two molecular equivalents of anhydrous ammonium perchlorate and one molecular equivalent of light precipitated magnesium oxide or carbonate 15 were ground together ina ball mill to a fineness estimated at about 200-mesh. The product resulting from the grinding was obtained in a satisfactor form for use as a dehydrator or water absor ent after'it had been heated,

either at ordinary pressures or at a vacuum approximating a quarter of an inch. The

. dried product was obtained in three to five hours by heating at this reduced pressure when the temperature was 250 C. Temperatures up to Q C. havebeen found useful, temperature of decomposition that is up to the of the perchlorate.

During the heating, ammonia and water I come oft, and also carbon dioxide if it is resso ent,-the reaction beginning at atmosp eric pressures and temperatures, as is shown by the odor ofammonia evolved on mixing the materials, but acceleration by heat and 'reduced pressure is usually desirable until the 35 reaction is complete. If an excess amount of ammonium perchlorate is employed the excess can be eliminated, if desired, by continued heat under'reduced .pressure.

When it is'desired to avoid basicity in the finished product an excess of the ammonium perchlorate may be employed. If a roduct is desired which will not'absorb car on dioxide an excess of magnesium carbonate may be employed.

The resulting anhydrous magnesium perchlorate absorbs both gaseous ammonia and water. In absorbing water it shows an. eagerness and thoroughness equal to phosphorous pentoxide and it absorbs three or more times It retains its granular porous form of the magnesium perc .1937. h Serial N0. 198,701.

-form'even when reheated to recover. the anhydrous form from the trihydrate.

The-water forms first the trihydrate with the magnesium perchlorate, and this is stable at temperatures up to 180 0., though it gives or up its water at easily obtainable higher temperatures.

The material, therefore, provides an easily operable method of obtaining anhydrous am monia from hydrous ammonia. It is only ea necessary to pass at a suitable pressure waterbearing ammonia gas over or through the magnesium perchlorate, cutting off the va or before the amount of water exceeds t at which can be taken up in forming the trie5 hydrate of magnesium perchlorate. Anhydrous ammonia is then given ofi, first at ordinary temperatures and pressures, and later, more completely at higher temperatures up to 180 C. After the ammonia gas come off, the water may be driven oil by heating the residue, the trihydrate, at temperatures above 180 C. and preferably below 350 C. thus regaining the anhydrous magnesium perchlorate. These anddrying procedures are greatly facilitated by the light hlorate when made from light magnesium oxide or carbonate.

' Having thus described certain embodiso ments of my invention, what I claim is: 1. Light granular magnesium perchlorate. 2. Granular magnesium perchlorate.

3. Granular magnesium perchlorate havingno affinity tor-carbon dioxide.

' '4. Anhydrous light magnesium perchlorate.

5. Anhydrous perchlorate.

6. Anhydrous granular magnesium perchlorate having no aifinity for carbon dioxide.

7.'The process of preparing ma esium perchlorate which consists in grin g together ammonium perchlorate and a magnesium compound which will react with it to form the magnesium perchlorate.

8. The process of preparing ma perchlorate which consists in grin ing together anhydrous ammonium perchlorate and a magnesium compound which will relight granularmagnesium esium has all 70 v 2 f Q y 1,788,980

act with it to form the magnesium perchlorate.

9. The process of preparing anhydrous v I magnesium perchlorate which consists in 5 grinding together anhydrous ammon um perchlorate and an anhydrous magneslum compound which will react with 1t to form the magnesium perchlorate, and drying the resulting product.

10. The process of preparing anhydrous a esium perchlorate w1th6ut afiinlty for ca'rfib n dioxide which consists in grinding together magnesium carbonate and ammonium perchlorate so that the magnesium carbonate 15 is in excess, and heating the resulting roduct at a temperature which will drive 0 water but not create a material afiinity for carbon dioxide.

11. The process of preparing anhydrous :0 ma nesium perchlorate without aflimty for car on dioxide which consists in grinding together anhydrous ammonium perchlorate to ether with a magnesium compound which wi lreact with it to form the magnesium per- 25 chlorate, there being present some excess of anhydrous magnesium carbonate, and heating the resulting product at a temperature which will drive ofi water but not create a material afiinity for carbon dioxide.

6 12. The process of preparin magnesium perchlorate suitable for water a rbmg purposes which consists in inding together ammonium perchlorate anf ight magnesiumbearinfi material which-will react with it to I form t e magnesium perchlorate, and heat' the material above 180 C. to drive off the water from the material.

GEORGE FREDERICK SMITH. 

